Swiftwick is constantly in PURSUIT of perfection, and nature's inspiration is the guide. Merino Wool, nature's original technical fiber, has proven insulating and wicking qualities. It keeps the skin dryer when sweating and cooler when hot. Swiftwick uses a 21-guage Australian Merino Wool with 3-inch minimum staple length strands for its soft finish, no-itch feel, and durability. The most hydrophilic of all natural fibers, absorbing as much as 30 percent of its weight without feeling wet, Merino Wool has the ability to disperse electrostatic charge resulting in less lint and dirt collection on the sock. The Swiftwick PURSUIT Line of Merino compression socks are made in America and The Best Socks You Will Ever Wear – Guaranteed.